We read with interest the March 2020 Practice Points article, "Define Your Pressure Injury Clinical Order Set within Your Workflow," by Cathy Thomas Hess, BSN, RN, CWOCN. Unfortunately, the author published an article in 2015 with similar information that does not reflect current research. As members of the small working group responsible for developing the nutrition chapter for the 2019 European Pressure Ulcer Advisory Panel, National Pressure Ulcer Advisory Panel, and Pan Pacific Pressure Injury Alliance's Prevention and Treatment of Pressure Ulcers/Injuries: Clinical Practice Guideline1 (2019 CPG) and as content experts in the field of nutrition and wound healing, we would like to clarify the recommendations presented. Most important: there are currently no laboratory tests that are sensitive indicators of nutrition status.
Albumin is not the basic tool to assess protein in relation to nutrition status, and current research indicates that low albumin levels are not directly related to the severity of protein deficiency but rather protein turnover and catabolism secondary to a substantial and systemic inflammatory background.1-6 This laboratory measure is not a sensitive measure of changes in nutrition status because of its long half-life of up to 20 days and large extravascular reserves. During a period of inflammation and/or stress, albumin is pulled from the extravascular space to the plasma (leakage attributable to increased vascular permeability) and returned when inflammation declines and Starling forces are restored. Because of this redistribution of reserves, albumin may remain normal even during mild starvation.
Current research indicates that using negative acute phase reactants, such as albumin and prealbumin, to measure nutrition status is no longer appropriate.1-6 Negative acute phase reactants are affected by the presence of inflammation, stress, hydration status, and renal function. Cytokine mediators redirect the liver to synthesize positive acute phase reactants, such as C-reactive protein and ferritin, rather than negative acute phase reactants. Marked inflammation increases the risk of malnutrition by increasing or altering the metabolism and utilization of protein. Hepatic protein levels do not accurately measure nutrition repletion in presence of systemic inflammation, thus making them poor markers of malnutrition. Further, albumin and prealbumin level levels increase with dehydration and decrease with overhydration; this does not impact nutrition status but may impair the healing process.
Studies support that hepatic proteins are a better indicator of morbidity, mortality, and illness severity than nutrition status.3,5,6 Research demonstrates that changes in acute phase proteins do not consistently or predictably change with weight loss, calorie restriction, or nitrogen balance. Therefore, the relevance of laboratory values as indicators of malnutrition is limited.
The Academy of Nutrition and Dietetics and the American Society for Parenteral and Enteral Nutrition define an etiology-based approach to describe a standard set of diagnostic characteristics to define malnutrition.1-4 These characteristics include insufficient energy intake, unintended weight loss, loss of muscle mass, loss of subcutaneous fat, localized or generalized fluid accumulation, and decreased functional status. The European Society of Parenteral and Enteral Nutrition and the 2018 Global Leadership Initiative in Malnutrition both support similar phenotypic criteria for defining malnutrition that do not include laboratory markers.1,2 The 2019 CPG1 does not recommend the use of laboratory tests of acute phase reactants as indicators of malnutrition based on the lack of research; serum albumin, prealbumin, and other laboratory values are important in determining overall prognosis, but the results do not correlate with defining an individual's nutrition status.1,2 The guideline also supports that serum protein levels may be affected by inflammation, renal function, hydration, and other factors and as such, they are not a good indicator of nutrition status.1
Registered dietitian nutritionists should be an integral part of the wound care team and can bring current information and research to light as more research is published. We refer readers to the March issue of Advances in Skin & Wound Care for the continuing education article, "The Role of Nutrition for Pressure Injury Prevention and Healing: the 2019 International Clinical Practice Guideline Recommendations" for additional information on this topic.2
-Emanuele Cereda, MD, PhD
Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
-Nancy Munoz, DNC, MHA, RDN, FAND
University of Massachusetts Amherst, Amherst, MA
- Mary Ellen Posthauer, RDN, LD, FAND
MEP Healthcare Dietary Services, Inc, Evansville, IN
- Jos Schols, MD, PhD
Maastricht University, Limburg, the Netherlands
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